The subject matter of this disclosure is generally related to systems that use shared cache, including but not limited to data storage systems that maintain large data sets and support multiple host applications and concurrent users. A data storage system may include multiple storage arrays. Each storage array may include a shared cache and multiple computing nodes that manage access to tangible data storage devices. The storage array presents one or more logical production volumes of storage to host applications running on a host. The host applications access the production volumes by sending IOs to the storage array. The computing nodes use the shared cache to temporarily store data that is being copied between the host and the tangible data storage devices.